SILENT PULMONARY EMBOLISM: INCIDENCE AND RISK FACTORS IN INDIAN PATIENTS WITH LOWER LIMB DVT

Dr.Shanmugavelayutham.C, Dr. Elancheralathan.K, Dr.Thulasikumar.G, Dr.Deepan kumar.B and Dr.Lakshmidharan.M. Department of Vascular Surgery, Stanley Medical College, Chennai. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

Pulmonary embolism (PE) with its associated mortality is the most devastating complication of Deep Venous Thrombosis (DVT). 9,10 There are various studies which show that Silent Pulmonary Embolism (SPE) is associated with increased conversion to symptomatic Pulmonary Embolism and with increased fatality. 8,9 Western literatures shows incidence of Silent PE from 50% to 80%. 1,2,8,9 The aim of our study is to evaluate the incidence of silent pulmonary embolism in Indian patients with lower limb deep venous thrombosis and analyzes the potential risk factors in patients with silent PE.

Methodology:
This is prospective observational study done in Stanley medical college in patients reporting to vascular surgery department with acute lower limb DVT from Jan 2015-Dec 2016. Totally 44 patients with acute lower limb DVT were studied with respect to various clinical factors. Only those with Proximal DVT were included in the study (involvement of deep venous thrombosis from popliteal vein and above). 5,6 All these patients had no symptoms (dyspnea, cough, pleuritic pain, haemoptysis, syncope) or signs (tachycardia, tachypnoea, hypotension, fall in ISSN: 2320-5407 Int. J. Adv. Res. 5(4), 2135-2138 2136 oxygen saturation) suggestive of PE. 2,3,4 These patients were submitted to CT pulmonary angiography for active detection of Pulmonary Embolism. All these patients were subjected to routine blood investigations, chest x-ray, ECG, echocardiogram, Ultra sonogram of Abdomen and Pelvis with appropriate hypercoagulable work up.

Results and Discussion:-
Incidence:-Out of 44 patients with acute lower limb proximal DVT, 33 were found to have silent pulmonary embolism with incidence of 75%. Data clearly indicate that Silent PE is very frequent in these groups of Indian patients with lower limb DVT.

Limb Involved:-
Overall prevalence of DVT is more on the left side constituting 55.56% of the cases. But incidence of Silent PE was found to be more on right side compared to left side (80% vs. 72%). In this study, 4 had bilateral DVT with incidence of 75% (3 out of 4).

Extent Of DVT:-
All the patients included in our study were proximal DVT patients. Of these, that involving iliofemoral segment had higher incidence of Silent PE than those involving femoropopliteal segment (84% vs. 62.5%). Out of three patients with inferior vena cava involvement, two were positive for silent PE (66.67%).
Ct Pulmonary Angiography:-Majority of patients had involvement of segmental pulmonary arteries constituting 84.8%. Also four patients in our study had involvement of one main pulmonary artery constituting 12% of patients but had no symptoms or signs. Those factors like blood investigations, X-ray, ECG and Echocardiography were not contributory for detecting Silent PE.

Conclusion:-
Above data (75%) clearly shows that silent PE is very frequent in Indian patients with deep venous thrombosis, with Proximal, Unprovoked DVT as significant risk factors. This very high incidence supports the need for screening and high levels of suspicion regarding this complication especially in those with proximal unprovoked DVT.